1. Field of the Invention
The present invention relates to an image forming apparatus and image forming method, and more particularly, to an inkjet recording apparatus in which solvent removal and image transfer can be performed without causing image disturbance, by provisionally fixing a solvent-insoluble material, such as coloring material, on an intermediate transfer body prior to the solvent removal and image transfer.
2. Description of the Related Art
An inkjet recording apparatus is provided with an inkjet head (which is hereinafter simply referred to as a “head”) having an ink ejection part including nozzles manufactured by using a high-precision processing technique, still it is difficult to print images on a large number of sheets at high speed by means of a direct recording method known in the related art, under the ejection conditions that have become extremely. Therefore, an inkjet method of intermediate transfer type has been proposed in order to improve reliability.
In the inkjet method of intermediate transfer type, an image is formed on a recording medium by forming a print image on the intermediate transfer body and then transferring the print image to the recording medium. In order to prevent disturbance of the image on the recording medium, process from the forming step of the print image on the intermediate transfer body to the transferring step of the image to the recording medium is important. In view of these circumstances, there is the following related art, for example.
Japanese Patent Application Publication No. 06-040023 discloses that liquid composed of an oil-based solvent and colored charged particles dispersed therein is deposited on the intermediate transfer body connected to earth, whereupon ions having the same polarity as the colored charged particles are applied. Thereby, the colored charged particles receive electrostatic force and move toward the surface of the intermediate transfer body, thus becoming provisionally fixed. However, this essentially utilizes the electrophoresis, then no solvent can be used other than the oil-based solvent having high insulating properties.
Japanese Patent Application Publication No. 2001-347747 discloses that a material which increases the viscosity when coming into contact with an ink liquid is deposited on the intermediate transfer body. The viscosity of the ink liquid is thereby adjusted so that the ink liquid sufficiently has both transferability from the intermediate transfer body to the recording medium and adhesiveness to the recording medium. This reference concentrates on the transfer conditions; however, it makes no mention of the provisional fixing of the coloring material contained in the ink liquid onto the intermediate transfer body, prior to the image transfer.
Japanese Patent Application Publication No. 2003-266658 discloses that a recording medium is laminated from a fixing layer and a permeable layer, a sublimating ink is deposited onto the permeable layer to form an image, the recording medium is then heated to transfer the image formed on the permeable layer to the fixing layer, whereupon the film of the permeable layer is peeled and removed from the recording medium. The recording medium is not reusable since the film of the permeable layer used for carrying out the image transfer is ultimately removed. Moreover, since the recording medium must have the permeable layer, there is no versatility in terms of the recording medium.
Japanese Patent Application Publication No. 2004-114675 discloses that a first material for improving the wetting properties is applied on the intermediate transfer body, a second material for reducing the fluidity of the ink is applied over the first material, then an image is formed on the intermediate transfer body by depositing the ink with an inkjet head, whereupon the image is transferred from the intermediate transfer body to the recording medium. Here, the coloring material is not fixed on the intermediate transfer body even provisionally, and hence there is a possibility that the coloring material is displaced and the image disturbance occurs, when transferring the coloring material to the recording medium.
Japanese Patent Application Publication No. 2003-191599 discloses an inkjet recording apparatus of intermediate transfer type constituted of an aggregate formation zone, an excess solvent removal zone, and an image transfer zone. In this inkjet recording apparatus, the coloring material is aggregated before removing the solvent, but not fixed on the intermediate transfer body even provisionally, and the image disturbance may occur when the solvent is removed.